A traditional plastic pipe molding apparatus includes an extruder which feeds molten plastic directly to one or more interior passages of die tooling which leads to a molding region of the extruder. The one or more die passages can be used to make single or even ribbed pipe.
The above apparatus suffers from the drawback that the extruder and the die tooling are fixed in position relative to one another. This necessitates relative large die tool which is expensive and which takes a substantial amount of time to heat. Space saving and heating benefits can be achieved by locating the extruder at a location remote from the die tooling and then using a plastic feed from the extruder to the die tooling. However, according to known practice, these benefits are more than offset by the fact that with the current design i.e., the design of the extruder being fixed relative to the die tooling the extruder is able to feed directly into the die passage of the tooling. Accordingly, distribution of the plastic from the extruder around the mouth of the die passage is achieved in a relatively simple manner. The same is not true when working with a remotely located extruder which will not necessarily align directly with the mouth of the die passage. Accordingly, using existing technology it is very difficult to take advantage of the benefits provided when separating an extruder from die tooling equipment of a pipe molding apparatus because such separation makes it very difficult to produce an even distribution of molten plastic from the extruder into the die passage. Without such even distribution the resulting pipe is produced with inconsistencies in the wall or walls of the pipe.